Jesuit writer on spiritual subjects, born at Moere Belgium, 17 May, 1811; died at Cincinnati, 29 July, 1865. He entered the Society of Jesus at Florissant, Missouri, in 1831. After the usual course of Jesuit training, he was appointed to teach in the colleges in the Missouri province of the Society. While engaged in teaching he proved himself to be a finished Greek scholar. During a dangerous illness, after his ordination as priest, Father Arnoudt bound himself by vow to labor with zeal to promote devotion to the Scared Heart of Jesus. Upon his recovery he wrote his great work, "De Imitatione Sacri Cordis Jesu". The manuscript of this work he sent to Rome in 1846, but through some mishap it was mislaid for ten years. After this period, having been approved by Father General Roothaan. the work was published "typis et sumptibus fratrum Caroli et Nicoli Benzinger" at Eisiedeln, 1863. It was translated into English by father Fastre and published at Cincinnati in 1865. Translations were made into French, German, Spanish, Portuguese, Italian, Flemish, and Hungarian. The French translation, published at Besancon, passed through eighteen editions between the years 1864 to 1887. Sommervogel gives the titles of two English, two Flemish, and four French versions of Father Arnouldt's work. Father de Smet, the missionary, is authority for the statement that Father Arnoudt left at his death the following manuscripts — a Greek epic poem of about 1,200 verses, a collection of Greek odes, and Greek grammar, and these ascetical works: "The Glories of Jesus", "The Delight of the Sacred Heart of Jesus", and a collection of spiritual retreats entitled "The Abode of the Sacred Heart".

Vanderspeeten, Notice biographique sur le P. Pierre Arnoudt, de la c. de J. (Tournay, 1873); de Smet in Precis historiques (1866). Also in the London ed. of The Imitation of the Sacred Heart (1867) and the Tournay ed. (1872) are published notices of the author by Russell and Van den Hofstadt respectively. Father Arnouldt's relatives in Belgium have preserved forty-six of his autograph letters.